Robert Brown is best known for his description of the phenomenon now known as Brownian motion. His major contribution to biology was the discovery of the cell nucleus. Brown realized that the nucleus is a characteristic component of almost all living cells. He carried out a broad range of pioneering microscopical work. In all of his meticulous work he demonstrated remarkable skill and the ability to draw conclusions of great theoretical importance.

Brown's father was a Scottish Episcopalian clergyman. Brown studied medicine at the universities of Aberdeen and Edinburgh before spending five years in the British army. From 1795 to 1800, he served in Ireland as an ensign and assistant surgeon. During a visit to London in 1798 he met Sir Joseph Banks (1743-1820), president of the Royal Society. With a recommendation to the Admiralty from Banks, Brown was able to obtain the position of naturalist on the Investigator, a ship...